Breast cancer has been associated to many risk factors like age, hormone replacement therapy and obesity, together with alcohol consumption. Several earlier studies have linked alcohol to breast cancer but they have not been consistent and also because smoking often accompanies drinking, researchers have not been sure that alcohol was the most important factor.
Now, researchers from Cancer Research, UK, who included dozens of the most prestigious researchers from around the world to look into the causes of cancer and reviewed the results of 65 separate studies, involving nearly 200,000 women say they are sure that it is the alcohol that matters.
They looked at two issues. The first was how much a woman needed to drink to increase her chance of breast cancer. The second was whether smoking increased this risk. They found that a single daily drink of 1 oz of spirits such as whiskey, gin, or vodka, or 3 oz of wine increases a woman's breast cancer risk slightly, perhaps 3% to 4%. But after that, every additional daily drink increases the risk by 7%. By four drinks a day, a woman's risk goes to 30%. Smoking however, did not make the risk worse. The researchers who also studied the life time risk of women, who drink, by age 80 found that while a non-drinker's chances were one in 11, a heavy drinker had about a one in seven chance of developing breast cancer by age 80. They also added that women's risk for breast cancer went up by 7% with each drink, no matter what the baseline risk (such as age, family history, HRT) was.
The researchers however concluded that alcohol drinking, in moderation, had beneficial effects on the heart.